An acoustic wireless network may be used to wirelessly transmit an acoustic signal, such as a vibration, via a tone transmission medium. In general, a given tone transmission medium will only permit communication within a certain frequency range; and, in some systems, this frequency range may be relatively small. Such systems may be referred to herein as spectrum-constrained systems. An example of a spectrum-constrained system is a well, such as a hydrocarbon well, that includes a plurality of communication nodes spaced-apart along a length thereof.
Known methods of installing and operating the nodes of such a network require significant time and energy. Nodes have been required to be installed on the casing in numeric order, requiring a large investment of time, an extended spatial footprint, and an extreme logistical plan for casing movement. Once installed in the well, operation of the network requires ongoing investigation of optimal operating conditions and potential networked node pairings. This is an iterative manual process requiring a significant testing time, and also drains energy of all nodes used to send the commands to perform the tests.
The above method also incurs significant risk. Incorrect numbering of the nodes or installation in the wrong order will result in an unworkable network, and extensive reconfiguration may be necessary to correct the mistake, costing substantial operator time and draining energy from a number of nodes on the network. Accidental misconfiguration while operating (such as assigning a duplicate or out-of-order number to a node, or linking them in an endless loop) carries with it a similar risk.
A typical method of addressing the numbering issue uses a central authority to number all manufactured nodes sequentially. This guarantees uniqueness but does not address out-of-order installation, nor does it prevent accidental misconfiguration, and the approach still requires the central authority to touch each node (to assign the number), thereby limiting manufacturing efficiency.
An alternate technique has each node assign itself a random number and eliminates the requirement to install nodes in sequential order. This removes the out-of-order risk and greatly reduces the risk of operational misconfiguration, but it cannot guarantee uniqueness because it is possible that two nodes will randomly assign themselves the same number. To minimize (though still not eliminate) the risk of duplicate numbers, a typical implementation makes the random number very large. Unfortunately, nodes must routinely transmit this number as part of each communication, so using a very large number leads to additional energy drain via excessive transmitted tones. What is needed is a method of identifying nodes in a network after installation and without using energy-draining random identification numbers.